Yeah it is pretty simple really. A crippled Bitcoin can not compete with alternative cryptocurrencies that can scale their blockchains directly, in regards to thinking LN is the solution to all problems, it most definitely is not especially considering that there are not even any decentralized solutions to routing between the different hubs, which will therefore lead to increased centralization in the form of this hub and spoke model.

You might think that adding all of this complexion and cost in the user experience is a good thing, but it most certainly is not. Nothing beats just being able to transact directly on a blockchain to transfer value between peers. Turning Bitcoin into a settlement layer for the lighting network would just be recreating part of the current financial system, becoming what Bitcoin was meant to counter in the first place.

We just need to increase the blocksize to keep up with demand, two megabyte blocks does not centralize the network like you claim, in my opinion having to rely on third parties to transact represents a much greater threat of centralization compared to just increasing the blocksize to two megabytes.

On chain transactions where always how Bitcoin was meant to operate, I am not against off chain solutions, I am just against crippling the Bitcoin network in order to "force" everyone to use off chain solutions. Even when Satoshi was still around people criticized this aspect, many engineers and computer scientists thought that this idea of all transactions being recorded on a shared ledger to be ridiculous. But that is what Bitcoin is, I understand that many people do not believe in this vision, it is clear that Core has diverged from this original vision. But I do still believe in it, and I would like to see the experiment be continued. If anything it should be the people that do not believe in this original vision that should move to alternative currencies instead of trying to change Bitcoin to conform to this alternative vision.

Fundamentally I believe technological growth will keep up with adoption, and even if it does not we should still scale Bitcoin as much as technology allows, nobody can predict the future, who are you to say that this will definitely not work, it depends on the relative rate of adoption and technological growth, both being unknowns. I think many here are guilty of the engineers nirvana fallacy. Which is that if Bitcoin can not scale to VISA levels today we should not scale Bitcoin directly at all, I believe this is deeply flawed.